Refrigerating apparatus with holdover means



y 4, 1965 w. D. AMMONS 3,181,310

REFRIGERATING APPARATUS WITH HOLDOVER MEANS Filed Sept. 3, 1963 FIG. 1.

' INVENTOR. FIG 4 WALTER ummows Z QMM T ATTORN United States Patent 3,181,310 REFRIGERATHNG APPARATUS WITH HOLDOVER MEANS Walter D. Amnions, 2020 SW. 18th Ave, Fort Lauderdale, Fla.

Filed Sept. 3, 1963, Ser. No. 305,976 3 Claims. (til. 62432) This invention relates to an electrically-operated apparatus for producing refrigerating temperatures within a suitable cabinet for the purpose, particularly such as are found in small boats and yachts which depend upon ice or dock current for maintenance of refrigerating conditions. More particularly, the present improvements relate to means for prolonging within such a cabinet the refrigerating temperatures long after the boat or yacht has left the clock when a further supply of ice or dock current is not available. In effect, this is a refrigerating apparatus with a special holdover feature inasmuch as it acts to maintain within the surrounding cabinet, while ice or electrical power (as the case may be) is not available, a freezing and/or refrigerating temperature which, under favorable conditions, may continue for 24 hours or so. The benefits and advantages of such a holdover apparatus are obvious since they enable a boat, which ordinarily must depend upon ice or dock current for its refrigeration, to proceed upon its way with assurance that food, beverages and perishables carried aboard will be preserved properly and maintained in a safe and palatable condition for an extended period of time.

I accomplish these objectives by a refrigerating apparatus which, when a power connection is available, will circulate a coolant through an evaporator coil system forming part of the present holdover unit. More particularly this unit is provided with adjacent superposed compartments, one of which is sealed to retain a eutectic composition in which are immersed certain interconnected coils and fins comprised in the evaporator unit. This composition, normally non-liquid and in a gel-like state, tends to become hard and more solid when its temperature is lowered to the eutectic point and therebelow, but with little or no volumetric change. At and near the eutectic point its heat absorbing capacity is at a maximum, thereby accelerating its accumulation of cold temperature units. Below this eutectic point the composition serves as an excellent medium for the storage of low temperature units long after the refrigerator apparatus has continued on an off-cycle period. In practice, the storage capacity of the eutectic composition, both as to time and temperature, is such that after six or more off-cycle hours it is still effective to re-freeze into cubes water which is held in the adjacent compartment. Additionally, this invention is concerned with various other features which contribute to the improved results achieved thereby, all as will be more fully explained hereinafter in connection with the accompanying drawing wherein is illustrated a preferred construction of the apparatus in the manner following:

FIGURE 1 is a diagrammatic view of a refrigerating system wherein the present holdover unit is incorporated;

FIG. 2 is a perspective view of the holdover unit, looking downwardly toward its front and one side thereof;

FIG. 3 is a vertical sectional view through the holdover unit, taken on line 33 of FIG. 4; a

FIG. 4 is a sectional view similar to FIG. 3, taken on line 44 of FIG. 3; and

FIG. 5 is a horizontal sectional view, taken on line 55 of FIG. 4.

The holdover unit with which the present invention is concerned is in the form of a box-like structure having upstanding sides which are joined by a bottom 12, and thereabove by two spaced shelves l5 and 16 the latter of which may appropriately be termed the static plate.

Front and back walls 17 and 18, respectively, are extended fast between the sides It and between the bottom 12 and lower shelf 15, thereby to define a closed compartment a which is sealed from the atmosphere to the outside thereof. A gravity-closing door 20, positioned above the front 17, is shown as hinged at its top to the sides 10 at top forward points thereof. In its normal down position, this door provides a closure for the two superposed compartments b and 0, both having a horizontal contour corresponding with the upper shelf 16 which separates the two compartments from each other. A desirable material from which to produce the structure just described is stainless steel in sheet form, its several compartments being fixedly united according to any approved means appropriate for the purpose.

The box-like structure, as herein illustrated, is formed with flanges 22 extending outwardly along the top edges of its sides lil, these flanges being provided with holes 23 for reception of fastening elements (not shown) by which to suspend the unit from the ceiling x (FIGS. 1 and 4) of a cabinet, refrigerator, or the like (not shown) wherein it is desired to position the holdover unit for operation. The back side of the holdover unit may remain spaced from the face y of the proximate cabinet wall, as suggested in FIG. 4. The door 20 which should face the front of the refrigerator cabinet is then disposed conveniently for manual operation with the aid of an attached handle 24; when swung upwardly to open position, against gravity, it exposes the two compartments b and 0 wherein certain food, beverages and/or ice cubes may be conveniently stored and maintained at a low temperature.

Carried by the lower shelf 15 is an evaporator unit comprising a coil system 25 which lies wholly within the bottom compartment a. The coils of this system, desirably copper tubing, extend through a horizontal zigzag course to traverse a plurality of closely-spaced, parallely-arranged vertical fins 26 having a high thermal conductivity, such as of aluminum or the like, to which they are intimately united frictionally or otherwise. The entire coil-fin unit is suspended as by flanges 27 which are outwardly turned from the endmost fins along their tops to engage the shelf 15 thereabove over an extended area and connect therewith through screw means 28 or the like. The sealed compartment a wherein the evaporator unit is suspended is also occupied by a eutectic composition 30 whose consistency is semi-solid or gel-like during prolonged offcycle periods. This composition substantially fills the bottom compartment so as to completely enclose the evaporator unit therein.

The static plate 16 also carries on its under face a second coil system 31 comprising a plurality of zigzag coils of copper or the like disposed in a horizontal course which contacts the under face of the said plate. Support is afforded to this coil system by thermal-conducting undulating strips 19 of aluminum or the like extended transversely of the coil system 31 to engage alternately the under side of each coil and therebetween the under face of the plate 16, these strips being connected thereto at intervals as by rivets 2?. An outlet end portion 32 which is extended downwardly from this coil system is joined by a coupling 33 with an upstanding inlet end portion 34 of the coil system 25 in the bottom compartment a. The outlet end portion 35 of this latter coil system is extended first upwardly and then downwardly through degrees at 36 to provide, in effect, a liquid trap. Both end portions 32 and 34 are extended through close-fitting holes in the lower shelf 15 where sealing mediums may be applied to prevent air leaks therethrough.

A coupling 37 beyond the trap connects the tube 35 with a tube 38 leading to the suction side of a motorcompressor unit 39 which is comprised in the refrigerating system as diagrammed in FIG. 1 where a capillary tube a 46 is shown as leading from the pressure side of the compressor unit through a filter-drier 41 and thence through a coupling 42 to the inlet end portion 43 of the coil system 31, thereby completing a circulatory system through which a suitable coolant is moved in response to operation of the compressor unit. A radiator 44 is also shown as series-connected into the circulatory system, adjacent the motor-compressor unit, to prevent overheating of the coolant therein.

As described, the coolant enters first into the upper coil system 31 where primary expansion takes place, then continues on through the lower coil system 25 before returning to the compressor for repeated re-circulation. A thermostat control 45 is connected electrically with the compressor unit and with a thermo-oulb 46 to hold the coolant at a selected temperature, as is common with current refrigerating systems. Energy for operation of the motor-compressor unit 39 is supplied through electrical conductors 48 and 49 connected with any convenient current source. In installations for which the present invention is designed, the compressor will often be located exteriorly of the cabinet wherein the holdover unit is mounted, the tubes '38 and 40 in the coolant system being then extended through the cabinet walls into the interior thereof to connect with the dual coil system of the holdover unit, as already described, through the line 38. This is advantageous since a coolant, such a Freon, for example, during off-cycle, tends to migrate to the coldest point in its circulatory system, and the trap thus provided by the high-up return band 36 acts to trap any excess liquid coolant at this point, thereby prolonging the life of the compressor unit.

With the compressor in operation, the minimum temperature will be maintained in the intermediate compartment b which is located between the coil system 31 thereabove and the coil system 25 therebelow. The temperature of the eutectic composition will then be about 15 degrees F. In this intermediate compartment the descent in temperature will be accelerated during each on-cycle period; when off, the temperature rise will be very slow. This is due largely to the presence in the sealed bottom compartment a of the fins 26 and of the eutectic composition 30 whose consistency changes to a more solid state. The fins act as a medium for effective transfer of tem perature units from the evaporator coil system. The eutectic composition also serves in a similar capacity and, more importantly, as a thermal reservoir to store and retain the low temperature units previously accumulated therein during an on-cycle period. Being then in a relatively solid state, its temperature-holding capacity is somewhat increased. It tends also to be self-sealing in event of any air leak into the closed compartment a wherein it is confined. To prevent mold growth in case of exposure to air, a suitable inhibitor may be added to the eutectic composition.

A satisfactory formula for a eutectic composition to be used with the present holdover apparatus is- Percent NA SO (anhydrous) 6 Carboxy methyl cellulose gum (Hercules Gum Type 3 Basic aluminum acetate .6

Formaldehyde .1

Water 90.3

While such a composition is being mixed, it remains in a liquid or watery state. In a very few minutes it will become a thick syrupy liquid, remaining so for approximately 1015 minutes, depending upon its temperature. In this state it can be readily poured into the bottom compartment a wherein the coil-fin unit will later be positioned when the shelf with which it is assembled is applied in place to provide a closure plate for this compartment. After this brief period, the composition tends to become a somewhat compressible, thick gel which cannot be poured, but can be cut or severed and then packed around and between any voids existing between the coils 25 and fins 26 or elsewhere in the surrounding compartment. This is the normal condition of the composition when its temperature is above the eutetic point. If desired, the eutectic point can be lowered by using other salt solutions which are prevented from separating therefrom by the gel state of the composition. The shelf 15, after being fitted over the compartment a, is then secured in place by any suitable means to provide a sealing closure therefor.

The present apparatus, when installed in a cabinet previously refrigerated by ice, will not involve replacement of any equipment. In such a case, the compressor unit might well be located exteriorly of the cabinet with the proper tubular connections extended therefrom to the evaporator unit which is suspended from the cabinet ceiling, as already described. Application of this improved holdover unit to a cabinet already equipped with a conventional electrical refrigerating apparatus requires only that its evaporator unit be replaced in order that the advantages of my invention be fully realized. It is assumed that any such cabinet designed for refrigeration will be suitably insulated, have a condensing unit of sufficient capacity, and also that its storage capacity will not exceed the capacity of the evaporator unit to produce the desired refrigerating temperatures therein. In a satisfactory installation, the temperature diiferential is from 15 to 20 degrees F. between that in the holdover unit and in the cabinet cxteriorly thereof, the former being well below 32 degrees F. with ample capacity to produce ice cubes if and when needed even at such times when an offcycle period has continued for a period of six or seven hours.

While I have shown and described the present apparatus as applied to the refrigeartor cabinet of a yacht, it may be used with equal advantage elsewhere where on and off power connections are commonly encountered, such as with trailers, trucks, etc., so any and all reference herein to yachts should be understood as applying broadly to various refrigerating cabinets wherein a similar environment in use exists.

I claim:

1. In a refrigerating apparatus having a coolant circulating system, means providing t'wo superposed compartments the lower of which comprises a bottom compartment and the upper of which comprises an upper compartment with a single relatively thin thermal-conducting separating plate therebetween, the bottom compartment being sealed against exposure to air to define a sealed compartment, a system of evaporator coils positioned in the sealed compartment with the coils arranged in a horizontal course adjacent the separating plate thereabove, a second evaporator coil system positioned in the upper compartment and disposed with its coils arranged in a horizontal course adjacent the top of said upper compartment, thermal-conducting means connecting with the plurality of coils in said bottom compartment and extending upwardly to engage over an extended area of the compartment top and comprising suspension means to suspend the coil system carried thereby, tubular connections between the two coils systems whereby coolant circulated through one of them continues on to circulate through the other, and thermal-conducting means comprising a eutectic composition disopsed within and substantially filling the bottom compartment so as to completely enclose the system of evaporator coils therein and being in contact with the separating plate thereabove to supplement the thermal-conducting suspension means for the proximate system of evaporator coils in transferring thermal units to the said plate and therethrough to the upper compartment whereby to cooperate with the second evaporator coil system therein in maintaining a temperature below the freezing point of water in said upper compartment.

2. A refrigerating apparatus according to claim 1 Wherein is provided a third compartment above the freezing compartment separated therefrom by a single thermalconducting plate constituting the top of the intermediate compartment immediately therebelow, the said second evaporator coil system being suspended from and disposed adjacent said last-mentioned thermal-conducting plate.

3. A refrigerating apparatus according to claim 2 wherein the structure including said three compartments is mounted within a cabinet in spaced relation to the inside face of its rear Wall, and wherein the tWo top compartments are open at the back for constant communication with the cabinet interior.

References Cited by the Examiner UNITED STATES PATENTS 2,061,856 11/36 Spohr 62-430 X 2,145,303 1/39 Jordan et al. 62 430 2,312,326 3/43 E6116 62-288 2,640,327 6/53 Alsing -1 62-443 X 2,677,664 5/54 TfiikBS 252-288 2,762,206 9/56 Ashley 62 5o3 X 2,800,454 7/57 Shepherd 252 70 2,803,115 8/57 Shepherd 252 70 X 3,130,163 4/64 Avera 252-67 3,135,323 6/64 Kleist 165-168 ROBERT A. OLEARY, Primary Examiner. 

1. IN A REFRIGERATING APPARATUS HAVING A COOLANT CIRCULATING SYSTEM, MEANS PROVIDING TWO SUPERPOSED COMPARTMENTS THE LOWER OF WHICH COMPRISES A BOTTOM COMPARTMENT AND THE UPPER OF WHICH COMPRISES AN UPPER COMPARTMENT WITH A SINGLE RELATIVELY THIN THERMAL-CONDUCTING SEPARATING PLATE THEREBETWEEN, THE BOTTOM COMPARTMENT BEING SEALED AGAINST EXPOSURE TO AIR TO DEFINE A SEALED COMPARTMENT, A SYSTEM OF EVAPORATOR COILS POSITIONED IN THE SEALED COMPARTMENT WITH THE COILS ARRANGED IN A HORIZONTAL COURSE ADJACENT THE SEPARATING PLATE THEREABOVE, A SECOND EVAPORATOR COIL SYSTEM POSITIONED IN THE UPPER COMPARTMENT AND DISPOSED WITH ITS COILS ARRANGED IN A HORIZONTAL COURSE ADJACENT THE TOP OF SAID UPPER COMPARTMENT, THERMAL-CONDUCTING MEANS CONNECTING WITH THE PLURALITY OF COILS IN SAID BOTTOM COMPARTMENT AND EXTENDING UPWARDLY TO ENGAGE OVER AN EXTENDED AREA OF THE COMPARTMENT TOP AND COMPRISING SUSPENSION MEANS TO SUSPEND THE COIL SYSTEM CARRIED THEREBY, TUBULAR CONNECTIONS BE- 